1. Field of the Invention
The present invention relates to a fabricating process of a circuit structure, and particularly relates to a fabricating process of a structure with an embedded circuit.
2. Description of Related Art
At present, the technology of embedded circuit board has been developed, which features that a circuit structure on the surface of a circuit board is embedded in a dielectric layer rather than protruded on the surface of the dielectric layer. FIGS. 1A through 1C illustrate a process flow for fabricating a conventional embedded circuit board.
First, referring to FIG. 1A, a substrate 110 is provided. A patterned dielectric layer 120 having a recess pattern 122 is formed on the substrate 110. The recess pattern 122 has a through hole 122a and a trench 122b. Next, referring to FIG. 1B, a seed layer (not shown) is formed on the patterned dielectric layer 120. Then, a copper layer 130 is formed by an electroless plating process and an electroplating process to fill the recess pattern 122. Thereafter, referring to FIG. 1C, the copper layer 130 is etched to form a conductive via 130a and a circuit 130b. 
According to the conventional technique, the copper layer 130 is required to fill the through hole 122a which is deeper and the trench 122b which is shallow, and the surface of the copper layer 130 needs to be substantially even. Hence, the copper layer 130 has larger thickness (about 20 micrometers). As a consequence, it takes more time to etch the copper layer 130, and the conductive via 130a and the circuit 130b, especially fine circuit, are easily damaged during the etching process.